A vertical structure was adopted for the east cofferdam for Tianjin central fishing port as the east cofferdam has been
planned for a yacht marina for the long term development. Prestressed sheet-piles were selected for the cofferdam construction
after repeated comparison and anchoring braced pile was used in anchoring structure. As a prestressed sheet-pile structure is
rather sensitive，this paper has in detail illustrated structural optimization design under the adverse conditions of soft earth
foundation. The prospect of sheet-pile structure application has been expanded and striking economic gain has been achieved by
the execution of this project.